Falkner and Boettcher, Appendix B, 1

Percentage Accurate: 99.2% → 99.2%
Time: 16.1s
Alternatives: 8
Speedup: N/A×

Specification

?
\[\begin{array}{l} \\ \cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right) \end{array} \]
(FPCore (v)
 :precision binary64
 (acos (/ (- 1.0 (* 5.0 (* v v))) (- (* v v) 1.0))))
double code(double v) {
	return acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0)));
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = acos(((1.0d0 - (5.0d0 * (v * v))) / ((v * v) - 1.0d0)))
end function
public static double code(double v) {
	return Math.acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0)));
}
def code(v):
	return math.acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0)))
function code(v)
	return acos(Float64(Float64(1.0 - Float64(5.0 * Float64(v * v))) / Float64(Float64(v * v) - 1.0)))
end
function tmp = code(v)
	tmp = acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0)));
end
code[v_] := N[ArcCos[N[(N[(1.0 - N[(5.0 * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(N[(v * v), $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 8 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 99.2% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right) \end{array} \]
(FPCore (v)
 :precision binary64
 (acos (/ (- 1.0 (* 5.0 (* v v))) (- (* v v) 1.0))))
double code(double v) {
	return acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0)));
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = acos(((1.0d0 - (5.0d0 * (v * v))) / ((v * v) - 1.0d0)))
end function
public static double code(double v) {
	return Math.acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0)));
}
def code(v):
	return math.acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0)))
function code(v)
	return acos(Float64(Float64(1.0 - Float64(5.0 * Float64(v * v))) / Float64(Float64(v * v) - 1.0)))
end
function tmp = code(v)
	tmp = acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0)));
end
code[v_] := N[ArcCos[N[(N[(1.0 - N[(5.0 * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(N[(v * v), $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)
\end{array}

Alternative 1: 99.2% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \cos^{-1} \left(\frac{\mathsf{fma}\left(v, v \cdot -5, 1\right) \cdot \mathsf{fma}\left(v, v, 1\right)}{\mathsf{fma}\left(v, v \cdot \left(v \cdot v\right), -1\right)}\right) \end{array} \]
(FPCore (v)
 :precision binary64
 (acos
  (/ (* (fma v (* v -5.0) 1.0) (fma v v 1.0)) (fma v (* v (* v v)) -1.0))))
double code(double v) {
	return acos(((fma(v, (v * -5.0), 1.0) * fma(v, v, 1.0)) / fma(v, (v * (v * v)), -1.0)));
}
function code(v)
	return acos(Float64(Float64(fma(v, Float64(v * -5.0), 1.0) * fma(v, v, 1.0)) / fma(v, Float64(v * Float64(v * v)), -1.0)))
end
code[v_] := N[ArcCos[N[(N[(N[(v * N[(v * -5.0), $MachinePrecision] + 1.0), $MachinePrecision] * N[(v * v + 1.0), $MachinePrecision]), $MachinePrecision] / N[(v * N[(v * N[(v * v), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\cos^{-1} \left(\frac{\mathsf{fma}\left(v, v \cdot -5, 1\right) \cdot \mathsf{fma}\left(v, v, 1\right)}{\mathsf{fma}\left(v, v \cdot \left(v \cdot v\right), -1\right)}\right)
\end{array}
Derivation
  1. Initial program 99.2%

    \[\cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. flip--N/A

      \[\leadsto \cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{\color{blue}{\frac{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1}{v \cdot v + 1}}}\right) \]
    2. associate-/r/N/A

      \[\leadsto \cos^{-1} \color{blue}{\left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1} \cdot \left(v \cdot v + 1\right)\right)} \]
    3. associate-*l/N/A

      \[\leadsto \cos^{-1} \color{blue}{\left(\frac{\left(1 - 5 \cdot \left(v \cdot v\right)\right) \cdot \left(v \cdot v + 1\right)}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1}\right)} \]
    4. /-lowering-/.f64N/A

      \[\leadsto \cos^{-1} \color{blue}{\left(\frac{\left(1 - 5 \cdot \left(v \cdot v\right)\right) \cdot \left(v \cdot v + 1\right)}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1}\right)} \]
    5. *-lowering-*.f64N/A

      \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\left(1 - 5 \cdot \left(v \cdot v\right)\right) \cdot \left(v \cdot v + 1\right)}}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1}\right) \]
    6. sub-negN/A

      \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\left(1 + \left(\mathsf{neg}\left(5 \cdot \left(v \cdot v\right)\right)\right)\right)} \cdot \left(v \cdot v + 1\right)}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1}\right) \]
    7. +-commutativeN/A

      \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\left(\left(\mathsf{neg}\left(5 \cdot \left(v \cdot v\right)\right)\right) + 1\right)} \cdot \left(v \cdot v + 1\right)}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1}\right) \]
    8. associate-*r*N/A

      \[\leadsto \cos^{-1} \left(\frac{\left(\left(\mathsf{neg}\left(\color{blue}{\left(5 \cdot v\right) \cdot v}\right)\right) + 1\right) \cdot \left(v \cdot v + 1\right)}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1}\right) \]
    9. *-commutativeN/A

      \[\leadsto \cos^{-1} \left(\frac{\left(\left(\mathsf{neg}\left(\color{blue}{v \cdot \left(5 \cdot v\right)}\right)\right) + 1\right) \cdot \left(v \cdot v + 1\right)}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1}\right) \]
    10. distribute-rgt-neg-inN/A

      \[\leadsto \cos^{-1} \left(\frac{\left(\color{blue}{v \cdot \left(\mathsf{neg}\left(5 \cdot v\right)\right)} + 1\right) \cdot \left(v \cdot v + 1\right)}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1}\right) \]
    11. accelerator-lowering-fma.f64N/A

      \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\mathsf{fma}\left(v, \mathsf{neg}\left(5 \cdot v\right), 1\right)} \cdot \left(v \cdot v + 1\right)}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1}\right) \]
    12. *-commutativeN/A

      \[\leadsto \cos^{-1} \left(\frac{\mathsf{fma}\left(v, \mathsf{neg}\left(\color{blue}{v \cdot 5}\right), 1\right) \cdot \left(v \cdot v + 1\right)}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1}\right) \]
    13. distribute-rgt-neg-inN/A

      \[\leadsto \cos^{-1} \left(\frac{\mathsf{fma}\left(v, \color{blue}{v \cdot \left(\mathsf{neg}\left(5\right)\right)}, 1\right) \cdot \left(v \cdot v + 1\right)}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1}\right) \]
    14. *-lowering-*.f64N/A

      \[\leadsto \cos^{-1} \left(\frac{\mathsf{fma}\left(v, \color{blue}{v \cdot \left(\mathsf{neg}\left(5\right)\right)}, 1\right) \cdot \left(v \cdot v + 1\right)}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1}\right) \]
    15. metadata-evalN/A

      \[\leadsto \cos^{-1} \left(\frac{\mathsf{fma}\left(v, v \cdot \color{blue}{-5}, 1\right) \cdot \left(v \cdot v + 1\right)}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1}\right) \]
    16. accelerator-lowering-fma.f64N/A

      \[\leadsto \cos^{-1} \left(\frac{\mathsf{fma}\left(v, v \cdot -5, 1\right) \cdot \color{blue}{\mathsf{fma}\left(v, v, 1\right)}}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - 1 \cdot 1}\right) \]
    17. metadata-evalN/A

      \[\leadsto \cos^{-1} \left(\frac{\mathsf{fma}\left(v, v \cdot -5, 1\right) \cdot \mathsf{fma}\left(v, v, 1\right)}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) - \color{blue}{1}}\right) \]
    18. sub-negN/A

      \[\leadsto \cos^{-1} \left(\frac{\mathsf{fma}\left(v, v \cdot -5, 1\right) \cdot \mathsf{fma}\left(v, v, 1\right)}{\color{blue}{\left(v \cdot v\right) \cdot \left(v \cdot v\right) + \left(\mathsf{neg}\left(1\right)\right)}}\right) \]
  4. Applied egg-rr99.2%

    \[\leadsto \cos^{-1} \color{blue}{\left(\frac{\mathsf{fma}\left(v, v \cdot -5, 1\right) \cdot \mathsf{fma}\left(v, v, 1\right)}{\mathsf{fma}\left(v, v \cdot \left(v \cdot v\right), -1\right)}\right)} \]
  5. Add Preprocessing

Alternative 2: 99.2% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\pi, 0.5, \mathsf{fma}\left(\pi, 0.5, -\cos^{-1} \left(\frac{\mathsf{fma}\left(v \cdot v, 5, -1\right)}{\mathsf{fma}\left(v, v, -1\right)}\right)\right)\right) \end{array} \]
(FPCore (v)
 :precision binary64
 (fma
  PI
  0.5
  (fma PI 0.5 (- (acos (/ (fma (* v v) 5.0 -1.0) (fma v v -1.0)))))))
double code(double v) {
	return fma(((double) M_PI), 0.5, fma(((double) M_PI), 0.5, -acos((fma((v * v), 5.0, -1.0) / fma(v, v, -1.0)))));
}
function code(v)
	return fma(pi, 0.5, fma(pi, 0.5, Float64(-acos(Float64(fma(Float64(v * v), 5.0, -1.0) / fma(v, v, -1.0))))))
end
code[v_] := N[(Pi * 0.5 + N[(Pi * 0.5 + (-N[ArcCos[N[(N[(N[(v * v), $MachinePrecision] * 5.0 + -1.0), $MachinePrecision] / N[(v * v + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision])), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left(\pi, 0.5, \mathsf{fma}\left(\pi, 0.5, -\cos^{-1} \left(\frac{\mathsf{fma}\left(v \cdot v, 5, -1\right)}{\mathsf{fma}\left(v, v, -1\right)}\right)\right)\right)
\end{array}
Derivation
  1. Initial program 99.2%

    \[\cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. acos-asinN/A

      \[\leadsto \color{blue}{\frac{\mathsf{PI}\left(\right)}{2} - \sin^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)} \]
    2. sub-negN/A

      \[\leadsto \color{blue}{\frac{\mathsf{PI}\left(\right)}{2} + \left(\mathsf{neg}\left(\sin^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)\right)\right)} \]
    3. div-invN/A

      \[\leadsto \color{blue}{\mathsf{PI}\left(\right) \cdot \frac{1}{2}} + \left(\mathsf{neg}\left(\sin^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)\right)\right) \]
    4. accelerator-lowering-fma.f64N/A

      \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{neg}\left(\sin^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)\right)\right)} \]
    5. PI-lowering-PI.f64N/A

      \[\leadsto \mathsf{fma}\left(\color{blue}{\mathsf{PI}\left(\right)}, \frac{1}{2}, \mathsf{neg}\left(\sin^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)\right)\right) \]
    6. metadata-evalN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \color{blue}{\frac{1}{2}}, \mathsf{neg}\left(\sin^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)\right)\right) \]
    7. asin-negN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \color{blue}{\sin^{-1} \left(\mathsf{neg}\left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)\right)}\right) \]
    8. distribute-frac-neg2N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \sin^{-1} \color{blue}{\left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}\right)}\right) \]
    9. asin-lowering-asin.f64N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \color{blue}{\sin^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}\right)}\right) \]
    10. distribute-frac-neg2N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \sin^{-1} \color{blue}{\left(\mathsf{neg}\left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)\right)}\right) \]
    11. distribute-frac-negN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \sin^{-1} \color{blue}{\left(\frac{\mathsf{neg}\left(\left(1 - 5 \cdot \left(v \cdot v\right)\right)\right)}{v \cdot v - 1}\right)}\right) \]
    12. /-lowering-/.f64N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \sin^{-1} \color{blue}{\left(\frac{\mathsf{neg}\left(\left(1 - 5 \cdot \left(v \cdot v\right)\right)\right)}{v \cdot v - 1}\right)}\right) \]
  4. Applied egg-rr99.2%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\pi, 0.5, \sin^{-1} \left(\frac{\mathsf{fma}\left(5, v \cdot v, -1\right)}{\mathsf{fma}\left(v, v, -1\right)}\right)\right)} \]
  5. Step-by-step derivation
    1. asin-acosN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \color{blue}{\frac{\mathsf{PI}\left(\right)}{2} - \cos^{-1} \left(\frac{5 \cdot \left(v \cdot v\right) + -1}{v \cdot v + -1}\right)}\right) \]
    2. sub-negN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \color{blue}{\frac{\mathsf{PI}\left(\right)}{2} + \left(\mathsf{neg}\left(\cos^{-1} \left(\frac{5 \cdot \left(v \cdot v\right) + -1}{v \cdot v + -1}\right)\right)\right)}\right) \]
    3. div-invN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \color{blue}{\mathsf{PI}\left(\right) \cdot \frac{1}{2}} + \left(\mathsf{neg}\left(\cos^{-1} \left(\frac{5 \cdot \left(v \cdot v\right) + -1}{v \cdot v + -1}\right)\right)\right)\right) \]
    4. metadata-evalN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{PI}\left(\right) \cdot \color{blue}{\frac{1}{2}} + \left(\mathsf{neg}\left(\cos^{-1} \left(\frac{5 \cdot \left(v \cdot v\right) + -1}{v \cdot v + -1}\right)\right)\right)\right) \]
    5. accelerator-lowering-fma.f64N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \color{blue}{\mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{neg}\left(\cos^{-1} \left(\frac{5 \cdot \left(v \cdot v\right) + -1}{v \cdot v + -1}\right)\right)\right)}\right) \]
    6. PI-lowering-PI.f64N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{fma}\left(\color{blue}{\mathsf{PI}\left(\right)}, \frac{1}{2}, \mathsf{neg}\left(\cos^{-1} \left(\frac{5 \cdot \left(v \cdot v\right) + -1}{v \cdot v + -1}\right)\right)\right)\right) \]
    7. neg-lowering-neg.f64N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \color{blue}{\mathsf{neg}\left(\cos^{-1} \left(\frac{5 \cdot \left(v \cdot v\right) + -1}{v \cdot v + -1}\right)\right)}\right)\right) \]
    8. acos-lowering-acos.f64N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{neg}\left(\color{blue}{\cos^{-1} \left(\frac{5 \cdot \left(v \cdot v\right) + -1}{v \cdot v + -1}\right)}\right)\right)\right) \]
    9. metadata-evalN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{neg}\left(\cos^{-1} \left(\frac{5 \cdot \left(v \cdot v\right) + -1}{v \cdot v + \color{blue}{\left(\mathsf{neg}\left(1\right)\right)}}\right)\right)\right)\right) \]
    10. sub-negN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{neg}\left(\cos^{-1} \left(\frac{5 \cdot \left(v \cdot v\right) + -1}{\color{blue}{v \cdot v - 1}}\right)\right)\right)\right) \]
    11. /-lowering-/.f64N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{neg}\left(\cos^{-1} \color{blue}{\left(\frac{5 \cdot \left(v \cdot v\right) + -1}{v \cdot v - 1}\right)}\right)\right)\right) \]
    12. *-commutativeN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{neg}\left(\cos^{-1} \left(\frac{\color{blue}{\left(v \cdot v\right) \cdot 5} + -1}{v \cdot v - 1}\right)\right)\right)\right) \]
    13. accelerator-lowering-fma.f64N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{neg}\left(\cos^{-1} \left(\frac{\color{blue}{\mathsf{fma}\left(v \cdot v, 5, -1\right)}}{v \cdot v - 1}\right)\right)\right)\right) \]
    14. *-lowering-*.f64N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{neg}\left(\cos^{-1} \left(\frac{\mathsf{fma}\left(\color{blue}{v \cdot v}, 5, -1\right)}{v \cdot v - 1}\right)\right)\right)\right) \]
    15. sub-negN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{neg}\left(\cos^{-1} \left(\frac{\mathsf{fma}\left(v \cdot v, 5, -1\right)}{\color{blue}{v \cdot v + \left(\mathsf{neg}\left(1\right)\right)}}\right)\right)\right)\right) \]
    16. metadata-evalN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{fma}\left(\mathsf{PI}\left(\right), \frac{1}{2}, \mathsf{neg}\left(\cos^{-1} \left(\frac{\mathsf{fma}\left(v \cdot v, 5, -1\right)}{v \cdot v + \color{blue}{-1}}\right)\right)\right)\right) \]
    17. accelerator-lowering-fma.f6499.2

      \[\leadsto \mathsf{fma}\left(\pi, 0.5, \mathsf{fma}\left(\pi, 0.5, -\cos^{-1} \left(\frac{\mathsf{fma}\left(v \cdot v, 5, -1\right)}{\color{blue}{\mathsf{fma}\left(v, v, -1\right)}}\right)\right)\right) \]
  6. Applied egg-rr99.2%

    \[\leadsto \mathsf{fma}\left(\pi, 0.5, \color{blue}{\mathsf{fma}\left(\pi, 0.5, -\cos^{-1} \left(\frac{\mathsf{fma}\left(v \cdot v, 5, -1\right)}{\mathsf{fma}\left(v, v, -1\right)}\right)\right)}\right) \]
  7. Add Preprocessing

Alternative 3: 99.2% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \pi - \cos^{-1} \left(\frac{\mathsf{fma}\left(5, v \cdot v, -1\right)}{\mathsf{fma}\left(v, v, -1\right)}\right) \end{array} \]
(FPCore (v)
 :precision binary64
 (- PI (acos (/ (fma 5.0 (* v v) -1.0) (fma v v -1.0)))))
double code(double v) {
	return ((double) M_PI) - acos((fma(5.0, (v * v), -1.0) / fma(v, v, -1.0)));
}
function code(v)
	return Float64(pi - acos(Float64(fma(5.0, Float64(v * v), -1.0) / fma(v, v, -1.0))))
end
code[v_] := N[(Pi - N[ArcCos[N[(N[(5.0 * N[(v * v), $MachinePrecision] + -1.0), $MachinePrecision] / N[(v * v + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\pi - \cos^{-1} \left(\frac{\mathsf{fma}\left(5, v \cdot v, -1\right)}{\mathsf{fma}\left(v, v, -1\right)}\right)
\end{array}
Derivation
  1. Initial program 99.2%

    \[\cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. frac-2negN/A

      \[\leadsto \cos^{-1} \color{blue}{\left(\frac{\mathsf{neg}\left(\left(1 - 5 \cdot \left(v \cdot v\right)\right)\right)}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}\right)} \]
    2. distribute-frac-negN/A

      \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{neg}\left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}\right)\right)} \]
    3. acos-negN/A

      \[\leadsto \color{blue}{\mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}\right)} \]
    4. --lowering--.f64N/A

      \[\leadsto \color{blue}{\mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}\right)} \]
    5. PI-lowering-PI.f64N/A

      \[\leadsto \color{blue}{\mathsf{PI}\left(\right)} - \cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}\right) \]
    6. acos-lowering-acos.f64N/A

      \[\leadsto \mathsf{PI}\left(\right) - \color{blue}{\cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}\right)} \]
    7. distribute-frac-neg2N/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \color{blue}{\left(\mathsf{neg}\left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)\right)} \]
    8. distribute-frac-negN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \color{blue}{\left(\frac{\mathsf{neg}\left(\left(1 - 5 \cdot \left(v \cdot v\right)\right)\right)}{v \cdot v - 1}\right)} \]
    9. /-lowering-/.f64N/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \color{blue}{\left(\frac{\mathsf{neg}\left(\left(1 - 5 \cdot \left(v \cdot v\right)\right)\right)}{v \cdot v - 1}\right)} \]
    10. sub-negN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\mathsf{neg}\left(\color{blue}{\left(1 + \left(\mathsf{neg}\left(5 \cdot \left(v \cdot v\right)\right)\right)\right)}\right)}{v \cdot v - 1}\right) \]
    11. +-commutativeN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\mathsf{neg}\left(\color{blue}{\left(\left(\mathsf{neg}\left(5 \cdot \left(v \cdot v\right)\right)\right) + 1\right)}\right)}{v \cdot v - 1}\right) \]
    12. distribute-neg-inN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\color{blue}{\left(\mathsf{neg}\left(\left(\mathsf{neg}\left(5 \cdot \left(v \cdot v\right)\right)\right)\right)\right) + \left(\mathsf{neg}\left(1\right)\right)}}{v \cdot v - 1}\right) \]
    13. remove-double-negN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\color{blue}{5 \cdot \left(v \cdot v\right)} + \left(\mathsf{neg}\left(1\right)\right)}{v \cdot v - 1}\right) \]
    14. accelerator-lowering-fma.f64N/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\color{blue}{\mathsf{fma}\left(5, v \cdot v, \mathsf{neg}\left(1\right)\right)}}{v \cdot v - 1}\right) \]
    15. *-lowering-*.f64N/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\mathsf{fma}\left(5, \color{blue}{v \cdot v}, \mathsf{neg}\left(1\right)\right)}{v \cdot v - 1}\right) \]
    16. metadata-evalN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\mathsf{fma}\left(5, v \cdot v, \color{blue}{-1}\right)}{v \cdot v - 1}\right) \]
    17. sub-negN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\mathsf{fma}\left(5, v \cdot v, -1\right)}{\color{blue}{v \cdot v + \left(\mathsf{neg}\left(1\right)\right)}}\right) \]
    18. accelerator-lowering-fma.f64N/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\mathsf{fma}\left(5, v \cdot v, -1\right)}{\color{blue}{\mathsf{fma}\left(v, v, \mathsf{neg}\left(1\right)\right)}}\right) \]
    19. metadata-eval99.2

      \[\leadsto \pi - \cos^{-1} \left(\frac{\mathsf{fma}\left(5, v \cdot v, -1\right)}{\mathsf{fma}\left(v, v, \color{blue}{-1}\right)}\right) \]
  4. Applied egg-rr99.2%

    \[\leadsto \color{blue}{\pi - \cos^{-1} \left(\frac{\mathsf{fma}\left(5, v \cdot v, -1\right)}{\mathsf{fma}\left(v, v, -1\right)}\right)} \]
  5. Add Preprocessing

Alternative 4: 99.2% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \cos^{-1} \left(\frac{\mathsf{fma}\left(v, v \cdot -5, 1\right)}{\mathsf{fma}\left(v, v, -1\right)}\right) \end{array} \]
(FPCore (v)
 :precision binary64
 (acos (/ (fma v (* v -5.0) 1.0) (fma v v -1.0))))
double code(double v) {
	return acos((fma(v, (v * -5.0), 1.0) / fma(v, v, -1.0)));
}
function code(v)
	return acos(Float64(fma(v, Float64(v * -5.0), 1.0) / fma(v, v, -1.0)))
end
code[v_] := N[ArcCos[N[(N[(v * N[(v * -5.0), $MachinePrecision] + 1.0), $MachinePrecision] / N[(v * v + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\cos^{-1} \left(\frac{\mathsf{fma}\left(v, v \cdot -5, 1\right)}{\mathsf{fma}\left(v, v, -1\right)}\right)
\end{array}
Derivation
  1. Initial program 99.2%

    \[\cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. acos-lowering-acos.f64N/A

      \[\leadsto \color{blue}{\cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)} \]
    2. /-lowering-/.f64N/A

      \[\leadsto \cos^{-1} \color{blue}{\left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)} \]
    3. sub-negN/A

      \[\leadsto \cos^{-1} \left(\frac{\color{blue}{1 + \left(\mathsf{neg}\left(5 \cdot \left(v \cdot v\right)\right)\right)}}{v \cdot v - 1}\right) \]
    4. +-commutativeN/A

      \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\left(\mathsf{neg}\left(5 \cdot \left(v \cdot v\right)\right)\right) + 1}}{v \cdot v - 1}\right) \]
    5. associate-*r*N/A

      \[\leadsto \cos^{-1} \left(\frac{\left(\mathsf{neg}\left(\color{blue}{\left(5 \cdot v\right) \cdot v}\right)\right) + 1}{v \cdot v - 1}\right) \]
    6. *-commutativeN/A

      \[\leadsto \cos^{-1} \left(\frac{\left(\mathsf{neg}\left(\color{blue}{v \cdot \left(5 \cdot v\right)}\right)\right) + 1}{v \cdot v - 1}\right) \]
    7. distribute-rgt-neg-inN/A

      \[\leadsto \cos^{-1} \left(\frac{\color{blue}{v \cdot \left(\mathsf{neg}\left(5 \cdot v\right)\right)} + 1}{v \cdot v - 1}\right) \]
    8. accelerator-lowering-fma.f64N/A

      \[\leadsto \cos^{-1} \left(\frac{\color{blue}{\mathsf{fma}\left(v, \mathsf{neg}\left(5 \cdot v\right), 1\right)}}{v \cdot v - 1}\right) \]
    9. *-commutativeN/A

      \[\leadsto \cos^{-1} \left(\frac{\mathsf{fma}\left(v, \mathsf{neg}\left(\color{blue}{v \cdot 5}\right), 1\right)}{v \cdot v - 1}\right) \]
    10. distribute-rgt-neg-inN/A

      \[\leadsto \cos^{-1} \left(\frac{\mathsf{fma}\left(v, \color{blue}{v \cdot \left(\mathsf{neg}\left(5\right)\right)}, 1\right)}{v \cdot v - 1}\right) \]
    11. *-lowering-*.f64N/A

      \[\leadsto \cos^{-1} \left(\frac{\mathsf{fma}\left(v, \color{blue}{v \cdot \left(\mathsf{neg}\left(5\right)\right)}, 1\right)}{v \cdot v - 1}\right) \]
    12. metadata-evalN/A

      \[\leadsto \cos^{-1} \left(\frac{\mathsf{fma}\left(v, v \cdot \color{blue}{-5}, 1\right)}{v \cdot v - 1}\right) \]
    13. sub-negN/A

      \[\leadsto \cos^{-1} \left(\frac{\mathsf{fma}\left(v, v \cdot -5, 1\right)}{\color{blue}{v \cdot v + \left(\mathsf{neg}\left(1\right)\right)}}\right) \]
    14. accelerator-lowering-fma.f64N/A

      \[\leadsto \cos^{-1} \left(\frac{\mathsf{fma}\left(v, v \cdot -5, 1\right)}{\color{blue}{\mathsf{fma}\left(v, v, \mathsf{neg}\left(1\right)\right)}}\right) \]
    15. metadata-eval99.2

      \[\leadsto \cos^{-1} \left(\frac{\mathsf{fma}\left(v, v \cdot -5, 1\right)}{\mathsf{fma}\left(v, v, \color{blue}{-1}\right)}\right) \]
  4. Applied egg-rr99.2%

    \[\leadsto \color{blue}{\cos^{-1} \left(\frac{\mathsf{fma}\left(v, v \cdot -5, 1\right)}{\mathsf{fma}\left(v, v, -1\right)}\right)} \]
  5. Add Preprocessing

Alternative 5: 98.9% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \cos^{-1} \left(\mathsf{fma}\left(v, v \cdot \mathsf{fma}\left(v \cdot v, 4, 4\right), -1\right)\right) \end{array} \]
(FPCore (v)
 :precision binary64
 (acos (fma v (* v (fma (* v v) 4.0 4.0)) -1.0)))
double code(double v) {
	return acos(fma(v, (v * fma((v * v), 4.0, 4.0)), -1.0));
}
function code(v)
	return acos(fma(v, Float64(v * fma(Float64(v * v), 4.0, 4.0)), -1.0))
end
code[v_] := N[ArcCos[N[(v * N[(v * N[(N[(v * v), $MachinePrecision] * 4.0 + 4.0), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\cos^{-1} \left(\mathsf{fma}\left(v, v \cdot \mathsf{fma}\left(v \cdot v, 4, 4\right), -1\right)\right)
\end{array}
Derivation
  1. Initial program 99.2%

    \[\cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right) \]
  2. Add Preprocessing
  3. Taylor expanded in v around 0

    \[\leadsto \cos^{-1} \color{blue}{\left({v}^{2} \cdot \left(4 + 4 \cdot {v}^{2}\right) - 1\right)} \]
  4. Step-by-step derivation
    1. sub-negN/A

      \[\leadsto \cos^{-1} \color{blue}{\left({v}^{2} \cdot \left(4 + 4 \cdot {v}^{2}\right) + \left(\mathsf{neg}\left(1\right)\right)\right)} \]
    2. unpow2N/A

      \[\leadsto \cos^{-1} \left(\color{blue}{\left(v \cdot v\right)} \cdot \left(4 + 4 \cdot {v}^{2}\right) + \left(\mathsf{neg}\left(1\right)\right)\right) \]
    3. associate-*l*N/A

      \[\leadsto \cos^{-1} \left(\color{blue}{v \cdot \left(v \cdot \left(4 + 4 \cdot {v}^{2}\right)\right)} + \left(\mathsf{neg}\left(1\right)\right)\right) \]
    4. *-commutativeN/A

      \[\leadsto \cos^{-1} \left(v \cdot \color{blue}{\left(\left(4 + 4 \cdot {v}^{2}\right) \cdot v\right)} + \left(\mathsf{neg}\left(1\right)\right)\right) \]
    5. metadata-evalN/A

      \[\leadsto \cos^{-1} \left(v \cdot \left(\left(4 + 4 \cdot {v}^{2}\right) \cdot v\right) + \color{blue}{-1}\right) \]
    6. accelerator-lowering-fma.f64N/A

      \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(v, \left(4 + 4 \cdot {v}^{2}\right) \cdot v, -1\right)\right)} \]
    7. *-commutativeN/A

      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(v, \color{blue}{v \cdot \left(4 + 4 \cdot {v}^{2}\right)}, -1\right)\right) \]
    8. *-lowering-*.f64N/A

      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(v, \color{blue}{v \cdot \left(4 + 4 \cdot {v}^{2}\right)}, -1\right)\right) \]
    9. +-commutativeN/A

      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(v, v \cdot \color{blue}{\left(4 \cdot {v}^{2} + 4\right)}, -1\right)\right) \]
    10. *-commutativeN/A

      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(v, v \cdot \left(\color{blue}{{v}^{2} \cdot 4} + 4\right), -1\right)\right) \]
    11. accelerator-lowering-fma.f64N/A

      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(v, v \cdot \color{blue}{\mathsf{fma}\left({v}^{2}, 4, 4\right)}, -1\right)\right) \]
    12. unpow2N/A

      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(v, v \cdot \mathsf{fma}\left(\color{blue}{v \cdot v}, 4, 4\right), -1\right)\right) \]
    13. *-lowering-*.f6498.6

      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(v, v \cdot \mathsf{fma}\left(\color{blue}{v \cdot v}, 4, 4\right), -1\right)\right) \]
  5. Simplified98.6%

    \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(v, v \cdot \mathsf{fma}\left(v \cdot v, 4, 4\right), -1\right)\right)} \]
  6. Add Preprocessing

Alternative 6: 98.7% accurate, 1.2× speedup?

\[\begin{array}{l} \\ \pi - \cos^{-1} \left(\mathsf{fma}\left(v, v \cdot -4, 1\right)\right) \end{array} \]
(FPCore (v) :precision binary64 (- PI (acos (fma v (* v -4.0) 1.0))))
double code(double v) {
	return ((double) M_PI) - acos(fma(v, (v * -4.0), 1.0));
}
function code(v)
	return Float64(pi - acos(fma(v, Float64(v * -4.0), 1.0)))
end
code[v_] := N[(Pi - N[ArcCos[N[(v * N[(v * -4.0), $MachinePrecision] + 1.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\pi - \cos^{-1} \left(\mathsf{fma}\left(v, v \cdot -4, 1\right)\right)
\end{array}
Derivation
  1. Initial program 99.2%

    \[\cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. frac-2negN/A

      \[\leadsto \cos^{-1} \color{blue}{\left(\frac{\mathsf{neg}\left(\left(1 - 5 \cdot \left(v \cdot v\right)\right)\right)}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}\right)} \]
    2. distribute-frac-negN/A

      \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{neg}\left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}\right)\right)} \]
    3. acos-negN/A

      \[\leadsto \color{blue}{\mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}\right)} \]
    4. --lowering--.f64N/A

      \[\leadsto \color{blue}{\mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}\right)} \]
    5. PI-lowering-PI.f64N/A

      \[\leadsto \color{blue}{\mathsf{PI}\left(\right)} - \cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}\right) \]
    6. acos-lowering-acos.f64N/A

      \[\leadsto \mathsf{PI}\left(\right) - \color{blue}{\cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{\mathsf{neg}\left(\left(v \cdot v - 1\right)\right)}\right)} \]
    7. distribute-frac-neg2N/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \color{blue}{\left(\mathsf{neg}\left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)\right)} \]
    8. distribute-frac-negN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \color{blue}{\left(\frac{\mathsf{neg}\left(\left(1 - 5 \cdot \left(v \cdot v\right)\right)\right)}{v \cdot v - 1}\right)} \]
    9. /-lowering-/.f64N/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \color{blue}{\left(\frac{\mathsf{neg}\left(\left(1 - 5 \cdot \left(v \cdot v\right)\right)\right)}{v \cdot v - 1}\right)} \]
    10. sub-negN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\mathsf{neg}\left(\color{blue}{\left(1 + \left(\mathsf{neg}\left(5 \cdot \left(v \cdot v\right)\right)\right)\right)}\right)}{v \cdot v - 1}\right) \]
    11. +-commutativeN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\mathsf{neg}\left(\color{blue}{\left(\left(\mathsf{neg}\left(5 \cdot \left(v \cdot v\right)\right)\right) + 1\right)}\right)}{v \cdot v - 1}\right) \]
    12. distribute-neg-inN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\color{blue}{\left(\mathsf{neg}\left(\left(\mathsf{neg}\left(5 \cdot \left(v \cdot v\right)\right)\right)\right)\right) + \left(\mathsf{neg}\left(1\right)\right)}}{v \cdot v - 1}\right) \]
    13. remove-double-negN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\color{blue}{5 \cdot \left(v \cdot v\right)} + \left(\mathsf{neg}\left(1\right)\right)}{v \cdot v - 1}\right) \]
    14. accelerator-lowering-fma.f64N/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\color{blue}{\mathsf{fma}\left(5, v \cdot v, \mathsf{neg}\left(1\right)\right)}}{v \cdot v - 1}\right) \]
    15. *-lowering-*.f64N/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\mathsf{fma}\left(5, \color{blue}{v \cdot v}, \mathsf{neg}\left(1\right)\right)}{v \cdot v - 1}\right) \]
    16. metadata-evalN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\mathsf{fma}\left(5, v \cdot v, \color{blue}{-1}\right)}{v \cdot v - 1}\right) \]
    17. sub-negN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\mathsf{fma}\left(5, v \cdot v, -1\right)}{\color{blue}{v \cdot v + \left(\mathsf{neg}\left(1\right)\right)}}\right) \]
    18. accelerator-lowering-fma.f64N/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\frac{\mathsf{fma}\left(5, v \cdot v, -1\right)}{\color{blue}{\mathsf{fma}\left(v, v, \mathsf{neg}\left(1\right)\right)}}\right) \]
    19. metadata-eval99.2

      \[\leadsto \pi - \cos^{-1} \left(\frac{\mathsf{fma}\left(5, v \cdot v, -1\right)}{\mathsf{fma}\left(v, v, \color{blue}{-1}\right)}\right) \]
  4. Applied egg-rr99.2%

    \[\leadsto \color{blue}{\pi - \cos^{-1} \left(\frac{\mathsf{fma}\left(5, v \cdot v, -1\right)}{\mathsf{fma}\left(v, v, -1\right)}\right)} \]
  5. Taylor expanded in v around 0

    \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \color{blue}{\left(1 + -4 \cdot {v}^{2}\right)} \]
  6. Step-by-step derivation
    1. +-commutativeN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \color{blue}{\left(-4 \cdot {v}^{2} + 1\right)} \]
    2. unpow2N/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(-4 \cdot \color{blue}{\left(v \cdot v\right)} + 1\right) \]
    3. associate-*r*N/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\color{blue}{\left(-4 \cdot v\right) \cdot v} + 1\right) \]
    4. *-commutativeN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\color{blue}{v \cdot \left(-4 \cdot v\right)} + 1\right) \]
    5. accelerator-lowering-fma.f64N/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(v, -4 \cdot v, 1\right)\right)} \]
    6. *-commutativeN/A

      \[\leadsto \mathsf{PI}\left(\right) - \cos^{-1} \left(\mathsf{fma}\left(v, \color{blue}{v \cdot -4}, 1\right)\right) \]
    7. *-lowering-*.f6498.1

      \[\leadsto \pi - \cos^{-1} \left(\mathsf{fma}\left(v, \color{blue}{v \cdot -4}, 1\right)\right) \]
  7. Simplified98.1%

    \[\leadsto \pi - \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(v, v \cdot -4, 1\right)\right)} \]
  8. Add Preprocessing

Alternative 7: 98.7% accurate, 1.2× speedup?

\[\begin{array}{l} \\ \cos^{-1} \left(\mathsf{fma}\left(v, v \cdot 4, -1\right)\right) \end{array} \]
(FPCore (v) :precision binary64 (acos (fma v (* v 4.0) -1.0)))
double code(double v) {
	return acos(fma(v, (v * 4.0), -1.0));
}
function code(v)
	return acos(fma(v, Float64(v * 4.0), -1.0))
end
code[v_] := N[ArcCos[N[(v * N[(v * 4.0), $MachinePrecision] + -1.0), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\cos^{-1} \left(\mathsf{fma}\left(v, v \cdot 4, -1\right)\right)
\end{array}
Derivation
  1. Initial program 99.2%

    \[\cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right) \]
  2. Add Preprocessing
  3. Taylor expanded in v around 0

    \[\leadsto \cos^{-1} \color{blue}{\left(4 \cdot {v}^{2} - 1\right)} \]
  4. Step-by-step derivation
    1. sub-negN/A

      \[\leadsto \cos^{-1} \color{blue}{\left(4 \cdot {v}^{2} + \left(\mathsf{neg}\left(1\right)\right)\right)} \]
    2. unpow2N/A

      \[\leadsto \cos^{-1} \left(4 \cdot \color{blue}{\left(v \cdot v\right)} + \left(\mathsf{neg}\left(1\right)\right)\right) \]
    3. associate-*r*N/A

      \[\leadsto \cos^{-1} \left(\color{blue}{\left(4 \cdot v\right) \cdot v} + \left(\mathsf{neg}\left(1\right)\right)\right) \]
    4. *-commutativeN/A

      \[\leadsto \cos^{-1} \left(\color{blue}{v \cdot \left(4 \cdot v\right)} + \left(\mathsf{neg}\left(1\right)\right)\right) \]
    5. metadata-evalN/A

      \[\leadsto \cos^{-1} \left(v \cdot \left(4 \cdot v\right) + \color{blue}{-1}\right) \]
    6. accelerator-lowering-fma.f64N/A

      \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(v, 4 \cdot v, -1\right)\right)} \]
    7. *-commutativeN/A

      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(v, \color{blue}{v \cdot 4}, -1\right)\right) \]
    8. *-lowering-*.f6498.1

      \[\leadsto \cos^{-1} \left(\mathsf{fma}\left(v, \color{blue}{v \cdot 4}, -1\right)\right) \]
  5. Simplified98.1%

    \[\leadsto \cos^{-1} \color{blue}{\left(\mathsf{fma}\left(v, v \cdot 4, -1\right)\right)} \]
  6. Add Preprocessing

Alternative 8: 98.0% accurate, 1.3× speedup?

\[\begin{array}{l} \\ \cos^{-1} -1 \end{array} \]
(FPCore (v) :precision binary64 (acos -1.0))
double code(double v) {
	return acos(-1.0);
}
real(8) function code(v)
    real(8), intent (in) :: v
    code = acos((-1.0d0))
end function
public static double code(double v) {
	return Math.acos(-1.0);
}
def code(v):
	return math.acos(-1.0)
function code(v)
	return acos(-1.0)
end
function tmp = code(v)
	tmp = acos(-1.0);
end
code[v_] := N[ArcCos[-1.0], $MachinePrecision]
\begin{array}{l}

\\
\cos^{-1} -1
\end{array}
Derivation
  1. Initial program 99.2%

    \[\cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right) \]
  2. Add Preprocessing
  3. Taylor expanded in v around 0

    \[\leadsto \cos^{-1} \color{blue}{-1} \]
  4. Step-by-step derivation
    1. Simplified97.0%

      \[\leadsto \cos^{-1} \color{blue}{-1} \]
    2. Add Preprocessing

    Reproduce

    ?
    herbie shell --seed 2024204 
    (FPCore (v)
      :name "Falkner and Boettcher, Appendix B, 1"
      :precision binary64
      (acos (/ (- 1.0 (* 5.0 (* v v))) (- (* v v) 1.0))))